126 S. W. Ford—Two new species of Primordial Fossils. 
much the appearance of corals; but the peculiar poriferous 
structure known to characterize a good typical species, the uni- 
form presence of a large walled central cavity, and the exist- 
ence in one species Ea ab Minganensis) of branched 
spicule would seem t y them more nearly to the spon 
By the late lamented Mr. Billings, to whom we owe our first 
knowledge of these singular forms, and who has discussed their 
affinities at considerable length, they were classed provisionally 
with the sponges; but in conclusion he remarks that ‘The re- 
semblance between the whole structure and that of the paleozoic 
corals seems also to show that in the Lower Silurian seas forms 
— combining the characters of the Protozoa and the Ce- 
lenterata.”* The existence of such forms in our older deposits 
is a ais of much interest, and it is to be hoped that contin- 
ued researches will add still further to our knowledge of them. 
This species occurs in conglomerate-limestone of the Lower 
Potsdam group at Troy, N. Y. 
Solenopleura nana, sp. nov.—Of this species I havea num- 
ber of specimens of the head, but they are all more or less im- 
perfect. The largest and best preserved specimen consists of a 
nearly perfect glabella and the greater portion of the fixed 
cheeks, and is but two lines in length. The glabella is nearly 
four-fifths the total length of the head and is especially charac- 
terized by its great relief. It is obtusely conical, slightly 
widest ome and is well defined all around by the dorsal fur- 
ws. a specimen two lines in length its highest point is 
nearly one and one-half lines above the base of the fix 
cheeks. It is marked on either side by two or three faint fur- 
rows. The fixed cheeks are notably convex, but their relief 
does not exceed one-third of that of the glabella. The eyes 
lar fillet. The dintance from the. eye to ‘the glabella is 
nearly equal to the width of the glabella at - mid length. 
The front margin is narrow and is bounded by a feebly convex 
rim, inside of which there is a narrow furrow hich gradually 
deepens on either side of the median line in passing outwart 
Between this furrow and the glabella there is a somewhat angu- 
lar ridge which widens in passing outward to the sutures. 
The course of the facial suture is nearly the same with that 
of Solenopleura brachymetopa of Angelin (Paleontologia Scan- 
dinavica, Pl. xix, fig. 1), but is directed slightly more inward 
in front of the eye. The neck-furrow is continuous all across. 
The exact form of the neck-segment cannot made out, 
owing to the damaged condition of all of the sections at this 
point. It is seen, however, to be less elevated than in the ma- 
* Pal. Boss., vol: i, p. 357. 
